Convergent deployment of ancestral functions during the evolution of mammalian flight membranes

Lateral flight membranes, or patagia, have evolved repeatedly in diverse mammalian lineages. While little is known about patagium development, its recurrent evolution may suggest a shared molecular basis. By combin-ing transcriptomics, developmental experiments, and mouse transgenics, we demonstrate that lateral Wnt5a expression in the marsupial sugar glider (Petaurus breviceps) promotes the differentiation of its patagium pri-mordium. We further show that this function of Wnt5a reprises ancestral roles in skin morphogenesis predating mammalian flight and has been convergently used during patagium evolution in eutherian bats. Moreover, we find that many genes involved in limb development have been redeployed during patagium outgrowth in both the sugar glider and bat. Together, our findings reveal that deeply conserved genetic toolkits contribute to the evolutionary transition to flight in mammals.

Automated summary

By combining transcriptomics, developmental experiments, and mouse transgenics, the researchers demonstrate that lateral Wnt5a expression promotes the development of patagium in marsupial sugar gliders. They also find that many genes involved in limb development have been redeployed during patagium outgrowth in both the sugar glider and bat. These findings reveal the deeply conserved genetic toolkits that contribute to the evolutionary transition to flight in mammals.